1. Field of the Inventions
The present inventions relate to a steering force detection device of a vehicle and, more particularly, to a steering force detection device that detects a steering force when a steering handle is rotated to a predetermined steering angle.
2. Description of the Related Art
Vehicles typically have a steering device for controlling the direction that the vehicle travels. Personal watercraft or small planing boats often have a steering handle for controlling the direction the vehicle travels. These vehicles typically have a throttle lever disposed in the vicinity of a grip of the steering handle. The throttle lever is operated to control the output of the engine. When the vehicles are maneuvered at low speeds, the engine output may be very low thereby reducing the steerability of the vehicle. Japanese Patent Publication No. JP-A-2001-329881 discloses operating a steering handle to increase the engine output for improving the steerability of the small planing boat when running at a low speed for docking.
Such watercraft often include a throttle opening detector for measuring the opening of a throttle valve controlled by the throttle lever. The steering angle of the steering handle can be measured by a steering angle detector. The speed of watercraft can be measured by a vehicle speed detector. The watercraft can have an engine output control for controlling the engine output. The engine output control increases the engine output when (1) the throttle opening detected by the throttle opening detector is equal to or less than a predetermined opening, (2) the steering angle detector measures a steering angle equal to or greater than a than a predetermined steering angle, and (3) the speed of the watercraft measured by the vehicle speed detector is equal to or greater than a predetermined value.
In the device of the JP-A-2001-329881 publication, the increase in engine output due to operation of the steering handle cannot be adjusted because of the engine output being increased automatically when the steering angle of the steering handle reaches the predetermined steering angle. On the other hand, the watercraft may be provided with a steering force detection device for controlling the engine output based on the steering force of the steering handle. However, the steering force detection device can be inaccurate, especially when the casing of the steering force detection device is not machined accurately.